Tens of thousands of people had the same level of classification access as Manning, but it took years for someone to reveal the blatant war crimes and lies to the public that he finally revealed.
It's not like you get a classified clearance and they hand you a flash drive with all the classified information in the world. An unbelievably large amount of information is classified. Most of it isn't remotely sensitive. Manning was working with information that was sensitive and that the vast majority of people with classified clearance didn't have access to.
And while Manning certainly made some things public that weren't known, newspapers regularly published stories about abuses by american soldiers and US attacks killing civilians long before Manning went public. I'm not trying to say what she did wasn't important just that the idea that some sort of conspiracy was keeping it under wraps is absurd. It's like the drug trade. We know there is a huge illegal drug trade going down. What individual informants do is give us the specifics about when, where and by who.
Yeah, that there was widespread military abuse was known. But it's not just that she fleshed out our knowledge about something that was already known, or that she told us some things we didn't know. There was stuff in there that directly contradicted important official statements that had been made to the public. Most memorable example for me: We'd been told repeatedly that the military doesn't keep official body counts, which allowed them to deflect the subject for years. But Manning's leaks showed us definitively that there were in fact official numbers, and that it was internally known Iraqi civilians made up over 60% of deaths. If that's not something being actively kept under wraps, I don't know what is.
Besides the point, anyway.
You can argue that some specific thing isn't true or doesn't count as a conspiracy, but the general stance that conspiracies can't/don't happen in the modern world is absurd to me. It's a major pet peeve of mine. But maybe our difference is in what we consider to be conspiracy.
To me, if a government organization is involved in or knows something that people deserve to know, but they choose to avoid disclosure, then it counts. Maybe it shouldn't. But we're kind of forced to use the word in this manner, when you get called a conspiracy theorist for trying to discuss things of that nature. For example, the old ACTA thread I pointed out. It was international trade politics being conducted in a manner that wasn't particularly extraordinary... but it's something that effects a large number of people, who knew something was going on there and wanted to know more, but the government refused to officially disclose information. And on this very forum, people were called conspiracy theorists for sharing what we did know thanks only to leaks.